U.S. Wind Power Finally Gets Its Sea Legs
The U.S. is a global leader in wind energy on land. But at sea? Not so much. As of this writing, the country’s only operating offshore turbine is a lone 20-kW windmill in Maine, called the VolturnUS. Meanwhile, Europe already has some 11 gigawatts of offshore wind capacity.
But the U.S. may catch up before long. This fall, a new wind farm will open on Block Island, off the coast of Rhode Island, and experts reckon it will be the first of many, now that several states have signed bills mandating the installation of offshore wind plants. Suzanne Tegen of the National Renewable Energy Lab and Cristina Archer of the University of Delaware explain.
Of course, wind energy does have an obvious drawback—sometimes the wind doesn’t blow. But engineers are experimenting with new ways to store energy during periods of low demand for use during peak hours. Michael Kintner-Meyer of the Pacific Northwest National Lab reviews a few of these innovations, including the idea of pumping compressed air into egg-shaped concrete balls underwater.
Cristina Archer is an associate professor in the College of Earth, Ocean, and Environment at the University of Delaware in Newark, Delaware.
Suzanne Tegen is Section Manager for Wind and Water Deployment at the National Renewable Energy Laboratory’s Wind Technology Center near Boulder, Colorado.
Michael Kintner-Meyer is a staff scientist at the Pacific Northwest National Laboratory in Richland, Washington.
JOHN DANKOSKY: This is Science Friday. I’m John Dankosky. Care to hazard a guess as to how many wind turbines there are on US soil? The answer, nearly 50,000. Yeah, we have 50,000 turbines on land.
Now, how many do you think we’ve got operating out at sea, off shore? I’ll give you a hint. The number is a bit smaller than that. OK, we’ve got one– one little tiny windmill, a junior-sized windmill, off the coast of Maine. Now that’s going to change pretty soon, because this fall, a much larger project, five full-size turbines, are set to start spinning off the coast of Rhode Island. Maybe it’ll give the naysayers who think “not in my backyard” a chance to see what these things look like. And since more states are signing on to install offshore wind farms, experts like my next guest say offshore wind could soon be blowing full speed ahead.
Cristina Archer is an associate professor in the College of Earth, Ocean, and Environment at the University of Delaware in Newark. Welcome to Science Friday.
CRISTINA ARCHER: Thank you very much.
JOHN DANKOSKY: And Suzanne Tegen is section manager for wind and water deployment at the National Renewable Energy Labs Wind Technology Center near Boulder, Colorado, and she joins us today from KGNU. Welcome to the show.
SUZANNE TEGEN: Glad to be here.
JOHN DANKOSKY: If you’ve got questions about wind power, 844-724-8255. That’s 844- SCI- TALK. Dr. Tegen, I’ll start with you, because I understand you actually took your summer vacation at Block Island, just to check out the new wind farm. Is this true?
SUZANNE TEGEN: It is true. Yes, that’s true. My husband has family in Rhode Island. So we visited them and then took the ferry out to Block Island, which is a beautiful ferry ride. And once we got there, we biked around the island. And you can bike up to the Southeast Lighthouse and see this amazing sight.
So I was with my husband and my two kids and some other family, and we got to see the installation happening. So there was one tower, and that was the day that the nacelle went up. The nacelle is kind of what houses the parts that make the wind power into electricity, way up at the top of the hub of the wind turbine. And so we got to see that happening. It was very exciting, and there were other people also visiting the lighthouse just for that purpose, to look out and see the new wind farm going up.
JOHN DANKOSKY: So this is pretty exciting for you. I understand not everyone is excited to see these out there, but for the most part, Dr. Tegen, people on Block Island seem pretty receptive to this.
SUZANNE TEGEN: Yeah, and so one of the things I study is community engagement and community involvement. And so I did talk to some community members, and pretty much everybody I talked to was very excited about this project. In fact, I tried to buy some souvenirs, like t-shirts or caps or something like that, to bring back to the Wind Technology Center or to my family, but they were all sold out. There were people really, really excited about this– not only the tourists that were there, but also the people who live there.
There was one tourist who had some negative things to say. He just said you used to be able to see the whole ocean from everywhere, you know, and now you can see these turbines. But of course, there is still a lot of ocean out there, and there’s one tiny little section where there are these five turbines.
Also, during the construction, there was a large jack-up barge there, so a big vessel, and that’s of course gone now. And all you have is the five turbines. And to me they’re beautiful, but you can always look, you know, the other way if you don’t love them.
But I do think that people will get used to them. And I’d love to hear, you know, what those naysayers think in five years, when they’re more used to them. And I think you’re right about people– once people see these things up and operating and benefit so much from the power, Block Island residents will have cheaper power because of them. So once they realize all of those things and see that they actually aren’t so bad, they’ll be more widely accepted.
JOHN DANKOSKY: From what I understand, the power is pretty expensive out on Block Island. They’re burning diesel fuel to get it. So this is a big change for them. Dr. Archer, how about you? Is this a pretty exciting time, you think, for offshore wind in the US?
CRISTINA ARCHER: Oh, it’s fantastic. It’s more than exciting, and I wish I could have gone to see the installation myself. I would have gone on vacation to see it. I will actually take my class to see the site, possibly at the end of next month. It’s an incredible– I can’t believe it’s finally happening, you know, five turbines in the water finally.
JOHN DANKOSKY: Well, you said you can’t believe it’s finally happening, and with that, it almost sounds like a little note of resignation there. There’s a lot of places in the world where there’s a lot more power. Why do you think it took so long, Dr. Archer?
CRISTINA ARCHER: Oh, yeah. It’s complicated, obviously, why it took so long. The previous case was Cape Wind, perhaps well known to people. They were trying to install a farm in the Nantucket Sound, and the project started– it was supposed to start, I don’t know. They started collecting data in 2003, collected data for a lot of– long time, and it didn’t happen. They were sued every other day. So it did not happen. In Europe, meanwhile, we have hundreds and hundreds of turbines in the water already, and they’ve been operating for a long time. So it’s a very exciting time, because it’s finally happening in the US.
SUZANNE TEGEN: And there’s been a lot of space– sorry, there’s been a lot of space on land in the US, you know, for turbines to go in, and that’s a lot less complicated. So turbines have been going in on land here, but in Europe, it’s more densely populated. So there isn’t that open space as much as we have it, and they’ve moved off shore sooner.
JOHN DANKOSKY: Well, Dr. Tegen, just explain a little bit how big this project is. I mean, we talk about five turbines, and we’re celebrating this. If we like the idea of offshore wind and this is very exciting, this isn’t a very big wind farm, is it?
SUZANNE TEGEN: No, this is not a very big wind farm when you look at other– so European offshore wind farms. It does look big, if you’re right up next to it. The towers are 175 meters high, and the hub height is 100 meters. So it will look big to people who haven’t seen other ones. But, right, there are commonly wind farms that are a lot bigger than this. And this one is, like you said, only 30 megawatts and five turbines, where we can see them in Europe with 20 turbines or more.
JOHN DANKOSKY: And just so we understand, that 30 megawatts powers about how many houses?
SUZANNE TEGEN: Well, so that depends. That’s a good question, and I’ve seen quoted– for example, in the New York Times, I saw 17,000 homes. I’ve seen 21,000 homes. But it really depends. Generally, we assume that one megawatt powers between 300 and 400 homes, but that’s homes that are in– that they have their residents in them for the whole year, whereas Block Island is much, much less populated in the wintertime. So they probably factored some of that in, I’m guessing, but so the ranges that I’ve seen are 17,000 to 21,000 homes.
JOHN DANKOSKY: So Dr. Archer, are there some advantages to putting wind turbines off shore, rather than on land? I mean, we have a lot of land in the central part of the United States and out west, certainly, and a lot of wind. But we also have an awful lot of offshore capacity. We’ve run into problems in trying to site them off shore so far, but what do you say are the advantages to putting these turbines out at sea?
CRISTINA ARCHER: Well, for the East Coast, I would say it’s almost your only wise choice. There isn’t that much wind inland along the East Coast. We don’t have really tall mountains. There’s not– the wind resource is not fantastic inland along the coast, and off shore, on the other hand, winds are whipping. It’s a very good idea to do it offshore.
In addition, the bathymetry, the depth of the ocean, is favorable also along the East Coast. The continental shelf is the right granite, and the depth is not very deep, so you can do foundations on a regular traditional way. So it’s not– you don’t have to go to floating turbines or anything like that. So you get the combination of good, good wind and the right depth, so it’s very favorable.
JOHN DANKOSKY: And explain that again for us. So these aren’t floating turbines. Some people might wonder that. They’re not floating off sea. These are anchored into the ground, right?
CRISTINA ARCHER: That’s right. They have foundations. Yeah.
JOHN DANKOSKY: OK, so, but there is such a thing as floating wind turbines. Are those being used anywhere in the world? Are they something that could come off shore to America?
CRISTINA ARCHER: Yeah, they are used. They’re a new technology, so they’re not widely used. There are a couple of examples, I believe, off shore of the UK. And Japan is considering the installation of some of them along the coast of Japan. And they are more expensive at the moment than traditional offshore turbines with a foundation. But they might be your only choice if you are in places like California, where the wind resource is excellent, especially in the summer, but the water is deep. And so you actually cannot do traditional turbines. You have to go with some kind of a floating technology.
JOHN DANKOSKY: People have some questions about this. Let’s go to Jeff, who’s calling from Greendale, Wisconsin. Hi there, Jeff. You’re on Science Friday.
JEFF: Hi, thanks for taking my call. Fascinating topic. Regarding the issue about people not wanting to see these, what about putting them just beyond the horizon, which I think is roughly 19 miles out? Obviously, it’s farther from the shore and a little more difficult to service. But then the other thought is, aren’t these very susceptible to being destroyed by hurricanes? And wouldn’t almost any hurricane coming through wipe out hundreds or thousands of these at a crack?
JOHN DANKOSKY: Two really good questions, and of course a hurricane has been bearing down on the East Coast here for the last couple of days, so maybe you can take that second question first. Dr. Tegen, why don’t you take that? Are we in some danger of getting all these windmills knocked over by the next big hurricane?
SUZANNE TEGEN: So the hurricane– the turbines that we design today are built to withstand Category 1 and Category 2 hurricanes. And we are working on designing turbines to withstand Category 3 hurricanes, which are a lot less common, of course, the farther north you go. And what happens, generally, is they stop spinning. So at a certain speed, when the winds get too high, the turbines will actually stop spinning. They’ll feather their blades and stop working. And so far, at least the design right now is we’re pretty positive that they’ll be able to withstand the Categories 1 and 2 hurricanes.
JOHN DANKOSKY: OK, so Jeff’s first question, though– and I’ll ask you, Dr. Archer. It’s this horizon question. I mean, people worry about being able to see these things off shore. Maybe they don’t like them. They don’t want them in their backyard, or in their view. So can’t we just put them out beyond the horizon?
CRISTINA ARCHER: Sure, it just costs more. And think about all the cables that you have to build to connect them. They become longer. Think about how much longer it takes to maintain them and do any kind of adjustments or maintenance to the turbines if you have to go farther. It’s not a bad idea, per se, because the farther away you go, the more the wind tends to be, the stronger the wind tends to be. So it would be beneficial from that point of view.
But then all these additional costs make it so that you have to kind of– to find some kind of a compromise. In addition, the depth, obviously, tends to get deeper too, and those costs become higher. But also you need to keep in mind that even let’s say at seven miles, you see the turbines only when it’s a spectacular day– sunny, no clouds, and no haze of any kind. If you have any kind of clouds, there’s a storm, there’s fog, you’re not going to see them. You’re just not going to see them.
SUZANNE TEGEN: And most of the turbines that are being proposed right now– so most of the projects that are being proposed are about 10 miles off shore. So this Block Island one is unusual. It’s actually in state waters, not in federal waters, which is unusual for offshore wind projects. But at least for the future of them, and probably the first few that our country sees will be closer in, because it’s– they’re– it’s easier to install. Maintenance will be easier.
But we have about 16 gigawatts– or up to 16 gigawatts in the pipeline, so that have been– proposals have been submitted for offshore wind development in the United States to the Bureau of Ocean Energy Management. And those ones are, like I said, about 10 miles offshore.
JOHN DANKOSKY: And you say we’ve got about 16 gigawatts in the pipeline. That’s compared to, I don’t know, how much in Europe that’s operational right now, Doctor?
SUZANNE TEGEN: I don’t know the– I’m not sure how many gigawatts there are in Europe off shore right now.
JOHN DANKOSKY: Because I’ve heard stories– I don’t know, Dr. Archer– that the country of Scotland was actually powering itself completely with offshore wind power not that terribly long ago. It’s a really big deal over there.
CRISTINA ARCHER: I didn’t hear that. It’s possible that maybe for a few hours they were powered just by offshore wind. Scotland, yeah, it is very windy, and there have been a lot of installations off shore of the UK. So– but I doubt that you can– yeah, I doubt that you can power the entire region for more than a few hours. Although I’m sure those hours were amazing, but–
JOHN DANKOSKY: Just a couple of really great hours. I’m John Dankosky. This is Science Friday from PRI, Public Radio International. I want to get to the phones again. Cynthia is calling from Bellingham, Washington. Hi there, Cynthia.
JOHN DANKOSKY: What’s on your mind, Cynthia?
CYNTHIA: Thanks for taking my call.
JOHN DANKOSKY: Yeah, of course.
CYNTHIA: Well, I know that on land, there’s been some unexpected negative impacts, as any time you introduce something new into Mother Nature’s system, something else goes kaflooey. And the wind has caused problems for both raptors– you know, killing eagles and other raptors– and then disrupting the bat population. And I wondered what they’ve found. The introduction of wind turbines out in the water, I would think there would be some impact on shore birds, waterfowl migration, and then also the disruption of light from above to the marine species that are sensitive to light.
JOHN DANKOSKY: Yeah, and also low-frequency sounds, that sort of thing. Dr. Archer, how can you– yeah. I mean, maybe you can address those questions. And Cynthia, thanks so much for those questions.
CRISTINA ARCHER: So the University of Delaware actually owns a wind turbine that is not technically off shore, but is very close to being an offshore turbine. It’s less than 200 meters from the ocean. And we have collected a lot of data on bird fatalities, bat fatalities, and any other accident that could have happened around the turbine.
And the numbers have been relatively, actually, small. The average is something like one raptor per year for the turbine. Something like– now I’m going by memory. I don’t– this is not exactly my field of expertise. But something like 15 bats per year were collected around the turbine, with a very intensive and very careful study.
And so it’s not a high number by any means. It’s an average number. It’s more of a myth that turbines kill so many birds and kill so many eagles. The bad reputation may come from the wind farm in California that is actually– was actually built on the migratory path of migratory birds, and so there was a high count at that farm, because it was in that particularly unlucky spot. In the rest of the world, the number of fatalities is actually very small. So I don’t know exactly about offshore turbines, because in the US we don’t have any to do any studies. But again, if the University of Delaware turbine is any representative of a coastal environment, we did not see any extra fatalities with respect to the average.
JOHN DANKOSKY: And Dr. Tegen, any worry about marine life?
SUZANNE TEGEN: I guess I– first of all, I would say that if you look at the bigger picture here, we are generating electricity from– you know, we’re producing electricity that doesn’t emit greenhouse gases. And so the wildlife is going to benefit from that. Our oceans are warming because of other electricity generation, and so they’re– you know, that’s, of course, an impact to them, a negative impact to them. So we also have to kind of look at this– we step back and look at the bigger picture of costs and benefits to marine life. But I will say that there is very careful thought going into this. Every project has siting considerations and, for example, the Block Island one was very collaborative.
JOHN DANKOSKY: And unfortunately we have to leave it there, because it’s such an exciting topic. Suzanne Tegen, thank you so much. Also Cristina Archer. Thank you for joining us. We’re going to be talking about storing some of that excess wind when we come back.
This is Science Friday. I’m John Dankosky. We’ve talked about all that wind energy that we might be capturing soon. But as you’ve probably experienced, the wind doesn’t always blow. So how can we save some of the energy from a windy day to use another time when we really need it? Michael Kintner-Meyer has a few ideas. He’s a staff scientist at the Pacific Northwest National Lab in Richland, Washington. Welcome to Science Friday.
MICHAEL KINTNER-MEYER: Good afternoon.
JOHN DANKOSKY: So first of all, how soon do you think we need to be thinking about storing all of this excess wind energy that we were just talking about? I mean, do we need to come up with a big storage solution pretty quick?
MICHAEL KINTNER-MEYER: Well, storage has already been used. It’s not really anything new. Regarding the integration and supporting the integration of variable renewables– wind and solar– we’re starting to see some potential issues there with not having enough flexibility. And these devices are really lending themselves to providing the flexibility.
So it is not necessarily an issue of not having enough capacity. It is often not having enough flexible capacity that is capable of ramping up very quickly when the wind comes down. And then likewise, being able to ramp down when the wind starts to blow again. And so it’s more these flexibility that’s causing potential problems. And so we’re seeing already some of these batteries, as well as non-battery solutions being deployed.
JOHN DANKOSKY: Of course, I mean, we all think about batteries as being the holy grail of storage, and if we could just get better batteries, then all of a sudden we’d be able to store all sorts of excess energy. But a lot of the things we wanted to talk about here were not necessarily battery ideas. I mean, thermal storage and other ideas. I mean, for instance, there’s a Canadian company investigating these concrete eggs that are underwater. Explain how those work.
MICHAEL KINTNER-MEYER: Yeah. The Canadian company technology is called Hydrostor. And so they’re using actually balloons that they are deploying down at the bottom of the seashore, and blowing up with compressed air. So it is basically a compressed air energy storage solution. We have a big compressor blowing air into these balloons that are being exposed to the hydrostatic pressure down on the sea floor. And you pump them up during charging periods, and then, if you like to release the energy, you reversing the flow, and the pressurized air and the high pressure is then being expanded in a turbine to reproduce electricity.
And so the interesting aspect of this technology is that you can deploy them pretty much anywhere, and the investor and manufacturer of this technology envisions to co-locate it with offshore wind deployment. So you can locate them very close to these offshore windmills that you just talked about, and firm up the electricity. So it’s a firming-up solution they have, so that the combined wind and storage solution gives you more predictable power.
JOHN DANKOSKY: And that provides some of the flexibility you were talking about before.
MICHAEL KINTNER-MEYER: Exactly.
JOHN DANKOSKY: So give us some other ideas about how to store excess energy– things that are working right now that maybe we don’t know about.
MICHAEL KINTNER-MEYER: Well, we have been using a pump tidal storage, where we converting electricity into potential energy by pumping water from a lower reservoir into an upper reservoir. And we can leave the water as long as we need it there, and when we need to discharge the storage, we reversing the flow. We opening up the spigot, and the water rushes down, turns the turbines, the water turbines, to generate electricity.
And so we have about a 22 gigawatts of capacity in the United States, which is about 2% of the installed capacity in about 10 one-terawatt, or 10,000-gigawatt, system. And that is quite an amount. Now, we have been using it for reserve capacity, particularly for being able to provide the electricity if big, large base load power plants are tripping off unexpectedly. So we have the ability to open up the spigot and then produce electricity very quickly. So only recently have we used it more for balancing activities, so that we can balance the fluctuation from wind and solar.
JOHN DANKOSKY: But it’s just such a simple idea. You have excess energy on a day, or maybe cheap energy overnight, and you just pump some water up a hill. And there are other ideas that are out there working like this. One that I heard about, it’s something like a train that’s up on top of a hill, and it comes down to release the energy?
MICHAEL KINTNER-MEYER: Yes, that’s an interesting other solution there. There are some developers out in the state of Nevada, and so they requested approval to build what they call an advanced rail energy storage system. So here again, the physical principle, very similar. You use electricity to turn it into potential energy by driving up an electrically-powered locomotive with rail cars that are filled with nothing but dirt up a hill. And by doing that, you storing energy and potential energy. And if you need the energy, you let the train roll down. You decelerating the train, and by decelerating it– by braking it, basically– you converting back the kinetic energy into electricity.
JOHN DANKOSKY: I was going to say, it sounds like some of these ideas are fairly simple ideas. But they take up a lot of space and a lot of infrastructure. I guess I’m wondering, Doctor, if battery technology, you know, as small as we can possibly get them, isn’t really the thing that we need to think about to be this flexible source of power, so that we don’t have to worry about building all this stuff, you know, giant trains and pumping water up hills.
MICHAEL KINTNER-MEYER: Well, what you’re seeing is you’re seeing a wide spectrum of different technologies being pursued. So we have flywheels that are being tested, and they are very successfully deployed. In the mid-Atlantic area, you seeing pump tidal. There’s several pump tidal installations that are in the pipeline.
But you’re seeing also these compressed air solutions there, that look for cavern in the ground. Now, their challenge is that you don’t have the right geological formations all over the place, and you’re looking for specific geological niches where you can deploy this. And you have other solutions there. The challenge is that each of these different technologies, whether that is a battery– like an electrochemical storage device or a mechanical storage device– has certain advantages and disadvantages. So a electrochemical storage does not scale very well, cost-wise, with unit energy. So if you want to add more energy, you need to have more batteries. So in the pump tidal, what makes really up the energy is more water in the upper reservoir. So the water is relatively cheap.
JOHN DANKOSKY: True.
MICHAEL KINTNER-MEYER: And likewise, with these trains, all you need is putting on more dirt or more rail cars on the train.
JOHN DANKOSKY: Yeah, well, you’re making a pretty good case for some of these very simple technologies. We didn’t even get a chance to talk about Ice Bears, where you use extra energy to make a big block of ice, and then use it as an air conditioner. There’s so many good ideas here.
Michael Kintner-Meyer is a staff scientist in the Pacific Northwest National Lab in Richland, Washington. Thanks so much for joining us today. I really appreciate it.
MICHAEL KINTNER-MEYER: You’re welcome. Thank you.